Fry the onions slowly until golden. Blend in the flour.
Add tomatoes and peppers and stir until boiling. Season with salt and pepper, add Worcestershire sauce and bay leaf.
Meanwhile parboil the sausages for 10 minutes; remove skins. Cut into thick diagonal slices.
Remove bay leaf from the sauce and add sausages. Tip mixture into a pie dish. Sprinkle top with the brown breadcrumbs and cheese.
Bake in the preheated oven for 30 minutes.
I often leave out the breadcrumb and cheese topping and just put everything into the casserole and cook slowly in a low oven. It's the sort of dish you can leave to cook slowly for hours.
Put everything into the casserole except the topping and cook on a very slow oven all day if necessary.
HEALTH ISSUE - Many people have IBS and don't know what causes it. I have found that red and green peppers cause mine with dire results. I have also read in a cookery book in Spain that if the skins are removed from peppers they are not so troublesome. As yet, I have not had the courage to try this but would be pleased to hear from others with the same allergy.